310 DWIGHT 



and flanks. Sides of head pale buft", black spotted ; submalar streaks black ; 

 distinct orbital ring rich buft". Bill and feet clay-color in dried skin, the upper 

 mandible sepia. This dress is grayer and with less buft than the correspond- 

 fhg plumage of T. u. swainsonii. 



Description from an Alaskan bird. 



3. First Winter Plumage acquired apparently by a partial 

 postjuvenal moult, in August in the far North, which involv^es 

 the body plumage and lesser wing coverts, but not the rest of 

 the wings nor the tail. 



Above, similar to corresponding plumage of T. Ji. sioainsonii, the olive-brown usu- 

 ally darker with less yellowish tinge, especially on the head. Below, with 

 no buff except a faint wash on the jugulum ; the sides of the head and breast 

 are therefore much grayer and the orbital^ring distinctly white. The buffy 

 edgings or terminal spots of the retained juvenal wing coverts are usually dis- 

 tinctive of the first winter dress. 



4. First Nupti.\l Plumage acquired by wear, birds becom- 

 ing very slightly grayer above. 



5. Adult Winter Plumage acquired by a complete post- 

 nuptial moult. Usually the edgings of the wing coverts are 

 uniform in color with the wings and the upper parts will aver- 

 age darker than in first winter dress. Young and old now be- 

 come indistinguishable. 



6. Adult Nuptial Plumage acquired by wear as in the 

 young bird. Distinguishable in many cases from first nuptial 

 by lacking the buffy wing edgings or spots which however may 

 be less obvious at this stage on account of wear. 



Female. — The sexes and moults are alike. 



Turdus aliciae bicknelli (Ridgw.). Bicknell's Thrush 



The moults and plumages correspond to those of T. alicia:. 

 A buffiness, which is lacking in T. alicicv, characterizes all 

 plumages but plumage differences are extremely small at every 

 stage. 



Turdus ustulatus swainsonii (Cab.). Olive-backed Thrush 



1. Natal Down. No specimen seen. 



2. Juvenal Plumage acquired by a complete postnatal moult. 



